How It Works-Book Of Dinosaurs

THE PREHISTORIC WORLD

Dinosaur habitats

Cretaceous plains

145 to 66 million years ago

Life was not easy on the Cretaceous plains. Dinosaurs

faced many changes to their habitat

Herds

Some dinosaurs survived

better in groups

The climate of the Cretaceous period

consisted of global temperatures of

around 10°C or 50°F higher than today

and high atmospheric carbon dioxide levels. It

was something of a greenhouse world. The

high sea levels (approximately 200-300m higher

than today) meant that swamp-like plains

existed on the lower latitude areas where

crocodylomorphs, such as the Simosuchus and

Deinosuchus, began to thrive. The

Deinosuchus, a member of the alligatoridae

family that includes modern day alligators,

weighed up to ten tons and was one of the most

ferocious predators in North A merica. In fact, its

habitat overlapped with tyrannosaurids, such

as Daspletosaurus; in these ecosystems it was

the powerful alligatorid, not the

tyrannosaurids, that dominated.

Also during the Cretaceous period, the skies

were inhabited by colossal pterosaurs, such as

the Quetzalcoatlus. These beasts rank as the

largest fl ying creatures of all time, with a

wingspan larger than many small planes.

However, thanks to a complex system of air sacs

inside its bone structure, the Quetzalcoatlus

weighed no more than 250kg. They were agile

and fast in the air, making catching prey easy.

Lots of different fl owering plants

evolved. Their pollen was spread by

insects like bees. Flowers eventually

outnumbered trees and shrubs

Flowers

During the Cretaceous

period, lightning struck trees

and started fi res. Because

there were plenty of plants,

fl ames could spread quickly

Wildfi res